A linear motion guide device includes a guide rail having rolling element rolling grooves in outer side faces, a slider including a rolling element rolling grooves in inner side faces so as to face with the rolling element rolling grooves of the guide rail, and provided in a slidable manner through multiple rolling elements loaded in load raceways each including the rolling element rolling grooves facing with each other, and a pair of end caps disposed at both ends of the slider so as to form endless circulation channels of the multiple rolling elements. Formed in the slider is a rolling element return channel that forms the endless circulation channel along the load raceways. The end cap has, to form the endless circulation channel, a scooping portion (tang portion) that scoops the rolling elements rolling over the load raceways, and a direction change channel that interconnects the load raceways and the rolling element return channel.
As an example application of the linear motion guide device, in an application under high temperature and vacuum environments, a plastic end cap is inapplicable. Hence, for the linear motion guide devices for such applications, the end cap is produced by Metal Injection Molding (MIM) using metal powders as a raw material (see, for example, Patent Document 1).
Conventionally, in order to improve a dimensional stability, an austeniticstainiess steel material that is a low-carbon material is used as the metal powder material. Since the austenitic stainless steel material is a low-carbon material, it is difficult to increase the hardness. Hence, a deformation and an abrasion gradually occur at the scooping portion of the end cap due to a collision with the rolling elements.
Hence, the technology disclosed in Patent Document 1 proposes an increase of the hardness of a required portion through work hardening like shot-peening, thereby suppressing an abrasion and a deformation.